This document specifies the Knoop hardness test method for metallic materials for test forces from 0,009 807 N to 19,613 N. The Knoop hardness test is specified in this document for length of the long diagonal e"0,020 mm. Using this method to determine Knoop hardness from smaller indentations is outside the scope of this document as results would suffer from large uncertainties due to the limitations of optical measurement and imperfections in tip geometry. The Knoop hardness test specified in this document is also applicable for metallic and other inorganic coatings. ISO 14577-1 allows the determination of hardness from smaller indentations. A periodic verification method is specified for routine checking of the testing machine in service by the user.